A plug-in hybrid electric vehicle (PHEV) employing both an electric motor and an engine, and as an electric vehicle (EV) driven by an electric motor without having an engine have been in widespread use. Vehicles such as the plug-in hybrid electric vehicle and the electric vehicle have a battery for driving an electric motor, and charge the battery by using an external charging station.
A method of charging a battery for driving a motor includes AC charging and DC charging. The DC charging standards include the CHAdeMO standard and the Combo standard. The charging station conforming to the CHAdeMO standard has a connector for DC charging and communicates with a vehicle via a Controller Area Network (CAN). Meanwhile, the charging station conforming to the Combo standard has connectors for DC charging and for AC charging, and performs power supply control by confirming the connected state with the vehicle, the completion of the preparation for charging, the state of charge and so on by a control pilot (CPLT) signal sent or received through a communication line.
Various information related to charging is sent and received between a vehicle and a charging station by PLC communication in which a control signal is superposed onto a control pilot signal.
Here, in the case where both of the DC charging standards are employed, a car manufacturer is required to comply with two types of the DC charging standards, resulting in increase in development costs.
Japanese Patent Application Laid-Open Publication No. 2014-124034 and No. 2014-124033 each discloses a relay device that achieves battery charging with electricity from charging stations having different DC charging standards with low costs by converting a control signal related to charging from one format to another and relaying the converted control signal between a vehicle and charging stations that are different in DC charging standards.